I was driving to work and when I pulled over and turned the car off, I noticed the light for the rear defrost function was flickering (manual controls).

It was colder today so the windshield (I think) was creaking which I assume is normal. So after driving few a few minutes and the engine is warmed up, I turn the temperature to the hottest setting and the airflow is blowing towards me; no fan, or anything else. Cabin warms up and the creaking stops. So continue on my merry way and notice it's getting a bit too warm for me so I turn the airflow towards the ground. I only mention this because that was the only thing I can think of that was different than what I normally do.

So with the flickering came my paranoia. I have the key in the ON position and am moving the airflow directions from cabin, cabin/ground, ground, ground/windshield, and just windshield. I hear what appears to be motor noise. I can only assume that's the doors shifting to adjust for the airflow settings. Also, turning on the defrost function or the recirculate functions also makes or click noise or the sound of something being rubbed against something. During normal driving, I can't hear any of this so I never notice these sounds. Just to see, I turn on the AC and fans and they all seem to work just fine.

I just got home to see and no lights flicker but I am wondering if this was a one time incident.

 

Well, took it to the dealer for an oil change and the service manager said he never heard of anything like it and since I was not able to replicate it, there was not much he could do. Since everything seems to work, I'll just assume it was a random glitch.

Also tried to sneak in the console squeak TSB but it was already out of warranty and wanted 115 dollars an hour... Yeah, I'll do it myself. That's what I get for doing research way after the fact.

 

Electrical switches and relays are mechanical devices. Sometimes a little bit of corrosion develops on a contact surface. Sometimes a bit of water condenses inside the unit, and can cause a short between the contacts. Corrosion is common in switches that are seldom operated. A flickering light often indicates that a switch is intermittently closed due to arcing, due to the presence of corrosion or water. Closing can also be due to vibration, if there is a spec of loose solder, or a broken part or weak spring inside the unit.

In many cases, operating the switch a few times scrapes the corrosion off of the contact, or allows a loose particle to fall to the bottom of the case. In many cases, a little bit of heat will evaporate the condensed water. Sometimes the switch or relay has to be replaced.